When operating hydraulic equipment conditions may arise when a sudden change in configuration causes voiding in hydraulic boom cylinders. For example, when an excavating bucket contacts the ground at the beginning of a dig, a reaction force against the bucket including support for the weight of the implement, may be transmitted through the stick and cause the boom to be pushed up faster than the boom cylinder can respond. This upward force can draw the rod and piston from the boom cylinder and cause a low pressure situation at the head end of the boom cylinders.
EP1416096A1 discloses a system that monitors for a number of conditions including low boom cylinder head end pressure to draw oil from the return line to the boom cylinder head end. The '096 reference fails to disclose a hydraulic circuit, components, and control system that meters fluid to a boom cylinder head end based on a defined point in the dig operation to reduce or eliminate voiding in the boom cylinder.